Search for single production of vector-like top partners at the Large Hadron Electron Collider

Abstract

The new vector-like top partners with charge $2/3$ are a typical feature of many new physics models beyond the Standard Model (SM). We propose a search strategy for single production of top partners $T$ focusing on both the $T\to Wb$ and $T\to th$ decay channels at the Large Hadron Electron Collider (LHeC). Our analysis is based on a simplified model in which the top partner is an $SU(2)$ singlet, with couplings only to the third generation of SM quarks. We study the observability of the single $T$ through the processes $e^{+}p\to T(\to b{W}^{+}){\bar{\nu }}_e\to b{\ell }^{+}+/E_T^{miss}$ and $e^{+}p\to T(\to th){\bar{\nu }}_e\to t(\to j{j}^{\prime }b)h(\to b\bar{b})/E_T^{miss}$ at the LHeC with the proposed 140 GeV electron beam (with $80\%$ polarization) and 7 TeV proton beam. For three typical $T$-quark masses (800, 900 and 1000 GeV), the $3\sigma$ exclusion limits on the $TWb$ coupling are respectively presented for various values of the integrated luminosity.

Comments: 12 pages, 12 figures, version accepted by Nuclear Physics B